Crossing the Line
by bluesnowflake44
Summary: Told from the perspective of both Derek and Casey, this story is about a brief moment or two from the episode "March Break" - so please don't read it if you haven't seen that amazing episode yet! Rated M for language and suggestive material. :P


Crossing the Line

A/N: OMFG, did you guys catch the "Life with Derek" episode that was on yesterday? GUH- THE **UST**! So much UST, in fact, that I was inspired to write this little ficlet. It's a one-shot, so I hope it's short but sweet. :)

Oh, and _italics represent subconscious thoughts._ Because Derek and Casey seem to be ignoring that part of themselves a bit too often for my taste. :P

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DEREK

_It can't be. She didn't just do that. No way. No way in hell._

My heart is already hammering in my chest enough. All those pranks she pulled on me: what with the girly laundry smell, the ping-pong chips, the hockey card kidnapping, the chocolate sauce on the phone… I'm impressed. She's getting so tricky, so clever. My hands start sweating just thinking about how much of an influence I've had on her. _It's so damn hot._ And the way her eyes widen when she's surprised (_they're so blue and big and gorgeous_), or how her lips press together if she's irritated (_is she __**purposefully**__ trying to draw attention to them or something?_), or how she places her hands just so on her hips if she thinks I've gone too far (_Jesus, I just want to shove her against the wall already_)…. She's so dramatic and intense even when she's being kinda bad-ass. Well, as bad-ass as Casey can be.

But once Casey McDonald stepped over that stupid, pink and blue line, I just couldn't even… I mean, it was just so… _forward_. I've hit on plenty of girls, made-out with most of them even, but I would bet all of Edwin's money that my keener step-sister would never – _could_ never – be so… obvious. I mean, even with my sweet sunglasses on, I could still plainly see how bold she was being. I had to say something, point it out to her and see if she realized just how obvious she was being.

"Ok, _that_ was the line, and you literally just crossed it." See what she makes of that!

Her eyes narrow. "No, _you_ crossed the line when you stole the ending of my book."

Wait… does she _still_ not get what I'm trying to point out? How much more obvious can _I_ make it?

But she's not done yet. "So guess what?" she continues, her eyes practically smoldering at me _and effecting me all over, dammit_. "Things are about to get ugly."

Woah, woah, woah. Was that… was that an invitation? She's not just berating me for doing something wrong. She's not simply threatening me with words. She's full-on **challenging **me to one-up her. _And God, is it hot how she does that. Why does she have to enunciate every word? It just draws more of my attention to those full, shiny lips of hers._

If she's ready to take this to the next level, I'm not about to skip out on a challenge. _And I'm certainly not about to let her get away with this, not if she's crossing the line and pretty much asking for it_.

So I whip off my sunglasses and stare her straight in the eye, _her gorgeous, big, blue eyes_, and I say (_just barely containing the husky desire in my voice)_, "Bring it."

I keep staring into her eyes, daring her to make the first move, defying her to back down like the coward she so often is. I may be cleverer, more devious, but if she ever found out my weakness, I might be in trouble.

And then, _fuckfuckfuckfuck_, her body shifts slightly (_or was I the one who took the first step?_) and then we're circling each other. _And God, it feels so feral, so openly intense, like we're just daring each other to make the first move. I don't even know if she's aware of it, but God, how could she __**not**__ be? _Her eyes never leave my face, and she's narrowed them and clenched her jaw _as if she wants me, too_, and I can't believe that she's being so un-Casey-like right now by defying me, by standing up to me, _by challenging me to just plain own up to the way her intensity turns me on, or to acknowledge how her closeness sends tingles dancing along my skin, or to just __**lean down and kiss her**__on those rosy lips that are __**just.**__**fucking. inches. **__from my own mouth. God, I think I'm going to do it, I really think I need to just press my mouth to hers and shove her against something and just… oh God, oh God, oh God_.

But she backs away _before I can do anything_, yet her eyes still hold a challenge, a defiance, and she lifts up two fingers to her eyes, then points them at me, and purrs (_just a little bit too huskily_), "I'm watching you." _My body's reacting completely by now, after that statement, and I don't know if I can hide it from her much longer… But, Jesus, I don't think I want to hide it anymore. I just want to grab her and…._

She takes a few more steps back (_dammit, why is she moving away from me?_) and whispers with more defiance, "Yeah."

And then, she's gone, hopping up the stairs _and showing off those long, long legs as she goes. _God, she's gotten good at this. She's gotten tricky. I stare after her, watching the empty space in front of me, and I can still see her there_. Can still feel the warmth radiating off of her body. Can still feel the_ anticipation of her hot mouth pressed against mine, devouring me, as I run my hands along those curves and finally learn what it's like to have her body up against mine, up against the doorway, on the staircase, the kitchen counter, the couch, her bed, my bed, any bed….

Oh fuck. No way. No fucking way. I think I have the hots for my _step-sister_. Jesus Christ, I just… I don't even know what to… oh _fuck_.

CASEY

I love reading, I really do. So when Derek stole the last page of my book, I just had to go find him _and see what he was up to_. I couldn't let him get away with it. _It had nothing to do with how obsessed I am with him_._ With how he moves, how he talks to other girls, the jokes he makes (best when at my expense, although I'll never admit it), or the way his tall body looks when he's standing in front of me or sprawled out over his bed_.

So I stormed downstairs, clutching the book in my hands (_because I had to clutch something to try to release all that pent-up frustration I have from the way he looks at me sometimes… all the time_). As soon as I got to the bottom of the stairs, the loud racket of his music blasted at my ears, and my eyes were assaulted (_entranced_) by the elementary jam session he was having with himself and his fake guitar. _Mmmm, he's got a nice butt. Oh, oh, oooh! He just lifted his arms and flashed his blue boxers at me. God, he looks good in that color. Actually, he looks great in brown, too: the brown of his shirt. I've always liked that color on him: it brings out the red in his hair. Hmm, his shirt's sort of clinging to his shoulders, and showing off the slight tapering from his shoulders to his waist…. Not that I'm checking him out or anything._

He goes over to his favorite chair and climbs on top of its armrest and the armrest of the couch, and keeps on rocking out. _He's so tall and long and lanky…._ But then he falls off, which serves him right for being so reckless to climb around on the furniture in the first place _and it gives me a nice view of his butt again. Woah, I wonder if he realizes just how warm it's getting in the house? It's not just me, is it? _

Maybe I should stop him before he gets hurt (_or sends any more shivers down my spine and along my skin and below my stomach—)_. "Ok, Derek," I snap (_in desperation_), "you can stop now." _Because you really, really need to stop before I pounce on you right this second!_

He doesn't stop. _Oh God, he's not stopping! I frantically try to remember what I'm doing down here in the first place. _ I need to ask him about where he put the last page of my book. _Yes, that's what it was._ Turning off the radio, I stand tall and firm, waiting to see what his reaction will be _and excited at the prospect of one of our little fights._

"What **are** ya doing?" he demands, waltzing over to me _in that sexy way that only Derek can achieve. And God, he's wearing some attractive sunglasses. _What's up with the headband? _It must be to protect his eyes from any sweat that trickles down his forehead, along the contours of his skin, into those hazel eyes of his…._ His hair poofs up all above his head, and he's slightly out of breath from all the dancing_. And I just want to yank those sunglasses off so I can stare into his eyes, and shove my mouth onto his and run my hands through his hair and then…._

"I'm on my side of the house," he states matter-of-factly.

_Um, what? I stumble for a minute, unsure of what he's referring to. Oh, right! The divisions I put up earlier! _"Where is the last page?" I demand, holding up my book.

He smirks _and it sends a brief but intense wave of heat across my body_. "Number one," he drawls, _as if he knows just what kind of effect he's having on me_, "I have no idea what you're talking about. And number two, **you**," he reaches over and grabs my shoulders (_oh my God, oh my God, why is he doing this to me? Why does he always have to torment me like this?!_), "are on **my** side of the house." He gives me a rough shove back across the pink and blue lines. _My skin still burns where his hands touched me, even with the fabric of my shirt between our skin. God, his arm reached across my body, across my chest, which is now tingling slightly and I don't think that's a normal feeling for me to be having about my step-brother_.

Oh, he just asked for it. He just rubbed my own rules into my face, _and I think my body's sort of taken on a mind of its own: a mind that responds best to the proximity of Derek_. So I clench my jaw, I lift my chin, and I step back over that damn line.

"Ok," he exclaims, taking a step back. _Wait… is he… could he possibly be uncomfortable by what I just did? And I swear he just gave me a once over. If only he wasn't wearing those stupid sunglasses, I could actually see his eyes and maybe figure out what's going through his head right now._ "**That **was the line and you literally just crossed it." Towards the end of the sentence, a smirk lights up his face and his words become more enunciated _as if he's struggling for his own control, maybe? Why does he have to speak so clearly? It only draws my eyes to his mouth…. God, I think he might just be catching on, might just have figured out how hot he makes me feel when he stands so close to me, heatedly arguing with me. I've got to go back to my safe excuse. What was it again? Oh yeah—_

"No, **you** crossed the line when you stole the ending of my book." I pause, _thinking that two can play at this game, so I speak just as slowly, enunciate just as much when I say_, "So guess what? Things are about to get ugly." I stare up at him, just asking for Derek to (_make the first move_) try to get the upper-hand. I'm not about to back down this time. _The air is too raw, the tension too thick. I can feel my blood surging through my veins and my breath getting more and more shallow. How can my stupid step-brother have so much of an effect on me?_

And then, the atmosphere shifts. He takes a step forward (_or did I? It's so hard to tell, all I can think about is how electrical the air feels, how close Derek's body is to mine, how much I want to just reach out to grab his shirt and pull his mouth to my own)_. Then we start circling each other, our eyes never leaving each other's faces. _And oh my GOD, I swear he's going to kiss me… if I don't kiss him first. My eyes are narrowed at him in annoyance – although what exactly it is about him that's making me annoyed, I can't really say. Something tells me, though, that I'm no longer frustrated about the fact that he stole my book. No, that's probably the last thing on my mind right now. What girl wants to think about reading when her body is going all hot and tingly and tight, and her heart is pounding in her ears, and she's staring into the eyes of her very hot, very __**close**__, step-brother as he circles her and she circles him. Like they're about to give in on some raw, deep-welled emotion that's lingered inside of them both for so long… too long._

_I've got to stop this. It isn't right. _So I lift up my hands and point two fingers at my eyes, then at Derek, and whisper (_just a bit too huskily_), "I'm watching you." _Back away, back away, back away!_ "Yeah," I add, _and can't help jutting out my lower lip just a little bit, hoping that Derek is turned on by it, that it torments him just like _his presence torments me, because he's just so incredibly irresistible sometimes, all the time, and I swear to God that one day I'm just going to grab the collar of his shirt and yank his face to mine – if he doesn't do it first. Because I swear that he wanted me, too, just then. I swear that I'm not imagining this – I may be a klutz, I may be oblivious sometimes, I may seem like I'm too far in the clouds… But what people don't realize is that it's **Derek** who makes me clumsy when I feel like he's staring at me. They don't understand that I'm oblivious to everything** but** Derek, because I'm always thinking about him, obsessing over him. And nobody would want to know that the only reason I seem like I'm in the clouds all the time is because I'm constantly imagining scenes about me and Derek, _always_ me and Derek. Because I can't deny it now: he's the guy I want. I tried to deny it so much to myself in the past, but there's really no point now. The tension between us is just too intense, too raw, too passionate, that I don't even care if it's forbidden.

But of course, it **is** forbidden. And I'm a rational person. I can be emotional, but I can't let this interfere in my life. I've got grades to keep, extra-curriculars to participate in, new families to keep intact. If I act on this, everything will change.

And as much as I want to, I shouldn't. I just… _can't_.

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A/N: Hope you guys enjoyed this as much as I enjoyed writing it. :) I was so BLOWN AWAY by how loudly this episode screamed "Dasey" that I just had to write it, simply to calm down my fangirl nerves. Lol. Anyway, please review – it'll make me want to write more if I know you guys are enjoying this!


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